The field of the present invention is air distribution systems for reciprocating pneumatic devices.
The present invention provides new features for the air distribution system of the air driven diaphragm pump disclosed in U.S. Pat. No. 5,957,670, the disclosure of which is incorporated herein by reference as if set forth here in full. Reference is also made to other disclosures of pumps and actuators found in U.S. Pat. Nos. 5,213,485; 5,169,296; 4,549,467; and 4,247,264. The foregoing patents are also incorporated herein by referenced. Another mechanism to drive an actuator valve is by solenoid such as disclosed in U.S. Pat. No. RE 38,239.
Reciprocating air distribution systems are employed to substantial advantage for driving pneumatically actuated equipment, such as air-driven double diaphragm pumps. These systems are advantageous when shop air or other convenient sources of pressurized air are available. Other pressurized gases are also used to drive these products. The term “air” is generically used to refer to any and all such gases. Driving products with pressurized air is often desirable because such systems avoid components which can create sparks. The actuators can also provide a constant source of pressure by simply being allowed to come to a stall point with the pressure equalized by the resistance of the driven device. As resistance by the driven device is reduced, the system will again begin to operate, creating a system of operations on demand.
A design consideration in the construction of reciprocating actuators is the prospect of developing ice within the device. Ice can disable operation and is most problematic in the exhaust. U.S. Pat. No. 5,957,670 addresses certain issues regarding actuator valve icing.
Other design considerations include performance. With reciprocating devices typically employing alternately charged pistons or diaphragms, increasing the size of the air flow passageways and decreasing flow restrictions improves device performance. This includes promoting flow from a source of pressurized air and rapidly reducing exhaust pressure to avoid resistance.
Air distribution systems providing reciprocating pressure have been made for air driven diaphragm pumps, among other devices. The pumps and associated distribution systems are typically of metal or of polymer material. The material has determined whether or not the device is statically dissipative, metal is and polymer is not. Certain applications require that the device be statically dissipative. A standard has been established for testing elements for their ability to dissipate static. Material considered not to be statically dissipative has a surface resistivity of 1×106 ohms or less under testing method ASTM D257.